A High-Resolution Foreground Model for the MWA EoR1 Field: Model and Implications for EoR Power Spectrum Analysis
MetadataShow full item record
The current generation of experiments aiming to detect the neutral hydrogen signal from the Epoch of Reionisation (EoR) is likely to be limited by systematic effects associated with removing foreground sources from target fields. In this paper we develop a model for the compact foreground sources in one of the target fields of the MWA's EoR key science experiment: the `EoR1' field. The model is based on both the MWA's GLEAM survey and GMRT 150 MHz data from the TGSS survey, the latter providing higher angular resolution and better astrometric accuracy for compact sources than is available from the MWA alone. The model contains 5049 sources, some of which have complicated morphology in MWA data, Fornax A being the most complex. The higher resolution data show that 13% of sources that appear point-like to the MWA have complicated morphology such as double and quad structure, with a typical separation of 33~arcsec. We derive an analytic expression for the error introduced into the EoR two-dimensional power spectrum due to peeling close double sources as single point sources and show that for the measured source properties, the error in the power spectrum is confined to high $k_\bot$ modes that do not affect the overall result for the large-scale cosmological signal of interest. The brightest ten mis-modelled sources in the field contribute 90% of the power bias in the data, suggesting that it is most critical to improve the models of the brightest sources. With this hybrid model we reprocess data from the EoR1 field and show a maximum of 8% improved calibration accuracy and a factor of two reduction in residual power in $k$-space from peeling these sources. Implications for future EoR experiments including the SKA are discussed in relation to the improvements obtained.
Showing items related by title, author, creator and subject.
Modelling the co-occurence of Streptococcus pneumoniae with other bacterial and viral pathogens in the upper respiratory tractJacoby, P.; Watson, K.; Bowman, J.; Taylor, A.; Riley, T.; Smith, D.; Lehmann, Deborah (2007)Go to ScienceDirect® Home Skip Main Navigation Links Brought to you by: The University of Western Australia Library Login: + Register Athens/Institution Login Not Registered? - User Name: Password: ...
The importance of wide-field foreground removal for 21 cm cosmology: a demonstration with early MWA epoch of reionization observationsPober, J.; Hazelton, B.; Beardsley, A.; Barry, N.; Martinot, Z.; Sullivan, I.; Morales, M.; Bell, M.; Bernardi, G.; Bhat, N.; Bowman, J.; Briggs, F.; Cappall, R.; Carroll, P.; Corey, B.; de Oliveira-Costar, A.; Deshpande, A.; Dillon, J.; Emrich, D.; Ewall-Wice, A.; Feng, L.; Goeke, R.; Greenhill, L.; Hewitt, J.; Hindson, L.; Hurley-Walker, N.; Jacobs, D.; Johnston-Hollitt, M.; Kaplan, D.; Kasper, J.; Kim, H.; Kittiwisit, P.; Kratzenberg, E.; Kudryavtseva, N.; Lenc, E.; Line, J.; Loeb, A.; Lonsdale, C.; Lynch, M.; McKinley, B.; McWhirter, S.; Mitchell, D.; Morgan, E.; Neben, A.; Oberoi, D.; Offringa, A.; Ord, S.; Paul, S.; Pindor, B.; Prabu, T.; Procopio, P.; Riding, J.; Rogers, A.; Roshi, A.; Sethi, S.; Shankar, N.; Srivani, K.; Subrahmanyan, R.; Tegmark, M.; Thyagarajan, N.; Tingay, Steven; Trott, C.; Waterson, M.; Wayth, Randall; Webster, R.; Whitney, A.; Williams, A.; Williams, C.; Wyithe, J. (2016)In this paper we present observations, simulations, and analysis demonstrating the direct connection between the location of foreground emission on the sky and its location in cosmological power spectra from interferometric ...
Darbyshire, James (2010)In the past five years, global interest regarding the development of renewable energy technologies has significantly increased. The conventional electric power generation methods sourced from fossil fuels is now problematic, ...